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Impact of midlatitude stationary waves on regional Hadley cells and ENSO
Author(s) -
Caballero Rodrigo,
Anderson Bruce T.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039668
Subject(s) - middle latitudes , hadley cell , el niño southern oscillation , climatology , atmospheric sciences , atmospheric wave , environmental science , geology , gravity wave , wave propagation , physics , climate change , general circulation model , oceanography , optics
Stationary planetary waves are excited in the midlatitudes, propagate equatorward and are absorbed in the subtropics. The impact these waves have on the tropical climate has yet to be fully unraveled. Previous work has shown that interannual variability of zonal‐mean stationary eddy stress is well correlated with interannual variability in Hadley cell strength. A separate line of research has shown that changes in midlatitude planetary waves local to the Pacific strongly affect ENSO variability. Here, we show that the two phenomena are in fact closely connected. Interannual variability of wave activity flux impinging on the subtropical central Pacific affects the local Hadley cell. The associated changes in subtropical subsidence affect the surface pressure field and wind stresses, which in turn affect ENSO. As a result, a winter with an anomalously weak Hadley cell tends to be followed a year later by an El Niño event.